Fibrous insulation is composed of many fine fibres that give the fibrous insulation a very large surface area relative to the volume it occupies. Each fibre traps a boundary layer of air, thereby providing the insulation function of the fibrous insulation. Rigid fibre insulations are typically set or cured by applying heat to a thermoset resin that binds the fibres into a rigid matrix. Heat is applied using high velocity heated air. Once cured or set, the insulation must be cooled. This requires a cooling fluid flow to be directed through the insulation, and can take a considerable amount of time.
Prior art cooling units have been devised to cool fibrous insulation. Generally, such cooling units include a high power fan that blows cooling air through the fibrous insulation at a high velocity. This high velocity cooling air is subsequently filtered by a filter system and then discharged into the atmosphere. Filtering is required as the cooling process strips not only the entrapped air and heat from the insulation, but also the smokes and fumes and other pollutants produced as a result of the high temperature curing of the thermoset resin.
Prior cooling units are often energy inefficient, and may also constitute a significant source of environmental pollution. Specifically, a lot of energy is consumed in producing high velocity air. Much of the energy required to impart this velocity to the air is lost, as the high velocity air is eventually discharged into the atmosphere after being blown through the fibrous insulation. Discharging heated high velocity air into the atmosphere also wastes the heat energy that has been stripped from the insulation product, and is, in addition, environmentally problematic, as pollutants from the insulation product may be discharged into the atmosphere.
Accordingly, a cooling unit that reduces the velocity requirements of the cooling fluid used to cool the insulation product, and that recovers heat from the cooling fluid after cooling, is desirable from an energy conservation perspective. From an environmental perspective, an improved cooling unit that facilitates the removal of pollutants before the cooling fluid is discharged into the atmosphere is also desirable.